Central and medial amygdaloid brain-derived neurotrophic factor signaling plays a critical role in alcohol-drinking and anxiety-like behaviors

Brain-derived neurotrophic factor (BDNF) is a member of the nerve growth factor family of neurotrophins and plays a vital role in synaptic plasticity. This study investigated the involvement of the amygdaloid BDNF system in molecular mechanisms underlying anxiety and alcohol-drinking behaviors. Male Sprague Dawley rats were cannulated targeting central amygdala (CeA), medial amygdala (MeA), or basolateral amygdala (BLA), and BDNF expression was manipulated using an antisense oligodeoxynucleotide (ODN) strategy. Anxiety-like and alcohol-drinking behaviors were measured after infusion of BDNF sense and antisense ODNs with or without BDNF coinfusion, using the elevated plus-maze test and two-bottle free-choice paradigm, respectively. Here we report that BDNF antisense ODN infusions into the CeA and MeA, but not BLA, provoked anxiety-like behaviors in rats, which were rescued by BDNF coinfusion. The levels of BDNF, p-ERK1/2 (phosphorylated extracellular signal-regulated kinases 1/2), and p-CREB (phosphorylated cAMP responsive-element binding protein) were decreased by BDNF antisense, but not by sense, ODN infusions, which were restored to normal after BDNF coinfusions. Furthermore, BDNF antisense ODN infusions into the CeA or MeA, but not into BLA, increased alcohol intake, which was attenuated by BDNF coinfusions. These novel results suggest that decreased BDNF levels in the CeA and MeA, but not in the BLA, are crucial in regulating alcohol-drinking and anxiety-like behaviors in rats.

BIG news in alcohol addiction: new findings on growth factor pathways BDNF, insulin, and GDNF

In recent years, it has become clear that growth factors are not only critical for the development of the central nervous system (CNS) but may also be important contributors to other neuronal functions in the adult brain. This symposium, presented at the 2005 RSA meeting, discussed evidence to support the hypothesis that alterations in growth factor pathways produce dramatic changes in the effects of alcohol on the CNS. The 4 speakers showed that the behavioral effects of alcohol in the adult are regulated by 3 growth factors, insulin, glial cell line-derived neurotrophic factor (GDNF), and brain-derived neurotrophic factor (BDNF). Dr. Wolf from the Heberlein laboratory presented findings obtained from genetic manipulations in Drosophila melanogaster, demonstrating that the insulin pathway controls sensitivity to the intoxicating effects of alcohol. Marian Logrip from the Ron and Janak laboratories presented evidence obtained in rodents that low concentrations of alcohol increase the expression of BDNF in the brain to regulate alcohol consumption. Dr. Pandey showed that amygdalar BDNF regulates alcohol's anxiolytic effects and preference. Finally, Dr. Janak presented evidence that increases in the expression of GDNF in the midbrain reduce alcohol self-administration in rats.

The decreased cyclic-AMP dependent-protein kinase A function in the nucleus accumbens: a role in alcohol drinking but not in anxiety-like behaviors in rats

The nucleus accumbens (NAc) brain structures have been implicated in the reward and reinforcing properties of ethanol. The present study investigated the role of nucleus accumbal cyclic AMP (cAMP)-dependent protein kinase A (PKA) signaling in alcohol drinking and anxiety-like behaviors of rats. It was found that infusion of PKA inhibitor (Rp-cAMP) into the NAc shell significantly increased the alcohol but not the sucrose intake, without modulating the anxiety-like behaviors, as measured by elevated plus maze test in rats. PKA inhibitor infusion into the NAc shell significantly decreased the protein levels of alpha-catalytic subunit of PKA (PKA-Calpha) and phosphorylated cAMP response element-binding protein (p-CREB) as well as decreased the protein levels of neuropeptide Y (NPY) in the shell but not in the NAc core of rats. On the other hand, infusion of PKA activator (Sp-cAMP) or NPY alone into the NAc shell did not produce any changes in alcohol intake; however, when these agents were coinfused with PKA inhibitor, they significantly attenuated the increases in alcohol preference induced by pharmacological inhibition of PKA. Interestingly, PKA activator coinfusion with PKA inhibitor into the NAc shell significantly normalized the PKA inhibitor-induced decreases in the protein levels of PKA-Calpha and p-CREB as well as of NPY in the NAc shell of rats. Taken together, these results provide the first evidence that decreased PKA function in the NAc shell is involved in alcohol drinking but not in anxiety-like behaviors of rats. Furthermore, decreased function of PKA may regulate alcohol drinking behaviors via CREB-mediated decreased expression of NPY in the NAc shell of rats.

Archform in cleft palate--a computerized tomographic classification

This prospective study was conducted in King George's Medical College, Lucknow, India amongst fifty cleft lip and palate cases to study the various arch forms. The maxillary arch form was traced from Computer Tomograph sections of all the cases pre and post-operatively. The various patterns of arch forms as observed from CT tracings exhibiting U & V shaped with sub-types denominated as posteriorly--convergent (c), divergent (d) and parallel (p). This simplified classification can be used in pediatric dentistry practice.

Deficits in amygdaloid cAMP-responsive element-binding protein signaling play a role in genetic predisposition to anxiety and alcoholism

We investigated the role of cAMP-responsive element-binding protein (CREB) in genetic predisposition to anxiety and alcohol-drinking behaviors using alcohol-preferring (P) and -nonpreferring (NP) rats. The levels of CREB, phosphorylated CREB, and neuropeptide Y (NPY) were innately lower in the central amygdala (CeA) and medial amygdala (MeA), but not in the basolateral amygdala (BLA), of P rats compared with NP rats. P rats displayed higher baseline anxiety-like behaviors and consumed higher amounts of alcohol compared with NP rats. Ethanol injection or voluntary intake reduced the higher anxiety levels in P rats. Ethanol also increased CREB function in the CeA and MeA, but not in the BLA, of P rats. Infusion of the PKA activator Sp-cAMP or NPY into the CeA decreased the alcohol intake and anxiety-like behaviors of P rats. PKA activator infusion also increased CREB function in the CeA of P rats. On the other hand, ethanol injection or voluntary intake did not produce any changes either in anxiety levels or on CREB function in the amygdaloid structures of NP rats. Interestingly, infusion of the PKA inhibitor Rp-cAMP into the CeA provoked anxiety-like behaviors and increased alcohol intake in NP rats. PKA inhibitor decreased CREB function in the CeA of NP rats. These novel results provide the first evidence to our knowledge that decreased CREB function in the CeA may be operative in maintaining the high anxiety and excessive alcohol-drinking behaviors of P rats.

The status of oral hygiene in cleft lip, palate patients after surgical correction

The cleft lip and palate patients usually present a number of problems viz. altered oral anatomy leading to changes in oral physiology diminishing the self-cleansing ability of individual. The handicapped children are unable to maintain their oral hygiene properly. The present study was formulated with the aim that does normalization of oral anatomy have its effect on improvement of oral hygiene? An assessment of oral hygiene index-simplified was performed between preoperative and postoperative values in the same patient at KGMU and KGDU. A total of 50 cases were recorded in two groups of 25 each: (i) 6 years. The observations are statistically analyzed by paired 't' test to get the significance of results.

RESULTS

The data analyzed showed the significant decrease in oral hygiene indices observed in both groups. A relative significance in oral hygiene status following surgery was observed. Both groups expressed greater significance when compared pre and postoperatively which is indicative of considerable improvement of oral hygiene after surgical correction. The study concludes that oral hygiene improves more in older cleft lip-palate cases following reconstruction of palatal vault, premaxilla and anterior lip seal by secondary bone grafting method when compared with oral hygiene indices results in primary periosteoplasty cases. The surgical correction of cleft lip palate enhances self-cleaning ability and better compliance to maintain oral hygiene in children as the age advances.

Radicular dens invaginatus--a case report

Case report showing classical Radicular dens invaginatus; along with in vitro illustrations of the extracted tooth and RVG (Radiovisiography) after radiopaque dye injection.

Lingual cysticercosis

A fourtyfive year old male presented with a painless solitary nodular swelling near left lateral border of the tongue of two months duration. Fine needle aspiration cytology lead to no conclusion. Excisional biopsy was done. Histopathology revealed Cysticercosis cellulosae and the parasite could be visualised in the slide along with the tongue muscles.

Estrogen decreases levels of calcineurin in rat amygdala and hippocampus

We examined the effects of estradiol benzoate (E2) on the protein expression of calcineurin in amygdaloid and hippocampal structures of ovariectomized (OVX) rats. Significant decreases in levels of calcineurin immunolabeling were seen in the medial and basomedial, but not central or basolateral, amygdala. Estrogen also reduced calcineurin immunoreactivity in the CA1 region of the hippocampus, but not in the CA3 region, hilus or ventral or dorsal dentate gyrus structures of hippocampus. These results indicate that E2 acts on calcineurin in a neuroanatomically specific manner and may be involved in estrogen-mediated regulation of gene expression.

CREB Gene Transcription Factors: Role in Molecular Mechanisms of Alcohol and Drug Addiction

This article presents the proceedings of a symposium presented at the meeting of the Research Society on Alcoholism, held in Vancouver, British Columbia, Canada, in June 2004. The organizers and chairpersons were Subhash C. Pandey and Fulton Crews. The presentations were (1) Ethanol Modulation of CREB: Role in Dependence and Withdrawal, by Fulton Crews; (2) Effects of D1 Dopamine Receptor Activation During Withdrawal From Chronic Morphine: Enhanced CREB Activation and Decreased Conditioned Place Aversion, by Elena H. Chartoff; (3) CREB-Haplodeficient Mice: Role in Anxiety and Alcohol-Drinking Behaviors, by Subhash C. Pandey; and (4) A Role for CREB in Stress and Drug Addiction, by Julie A. Blendy.

Partial deletion of the cAMP response element-binding protein gene promotes alcohol-drinking behaviors

The cAMP response element-binding protein (CREB) gene transcription factor has been shown to play a role in the synaptic plasticity associated with drug addictive behaviors; however, the causal role of the CREB gene in alcohol-drinking behaviors is unknown. The present investigation evaluated alcohol-drinking behaviors in mice that are haplodeficient in CREB as a result of targeted CREB (alpha and Delta) gene disruption. It was found that CREB-haplodeficient (+/-) mice have higher preference for ethanol but not for sucrose solution than wild-type (+/+) littermates. The functional aspects of the CREB gene transcription factor were also investigated by measuring the protein levels of phosphorylated CREB (p-CREB) and the expression of cAMP-inducible genes such as neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF). Deletion of the CREB (alpha and Delta) gene significantly decreases total CREB, p-CREB levels and the expression of NPY and BDNF in the brain structures of CREB-deficient (+/-) mice. It was also found that CREB-deficient (+/-) mice displayed more anxiety-like behaviors and that acute ethanol exposure produced anxiolytic effects and significantly increased protein levels of p-CREB and NPY in the central and medial but not in the basolateral amygdala of wild-type mice, but these effects are attenuated in CREB-deficient mice compared with wild-type mice. These results provide the first direct evidence that a haplodeficiency of the CREB gene is associated with increased alcohol-drinking behaviors. Furthermore, alcohol drinking and anxiety-like behaviors in CREB-haplodeficient mice may possibly be related to decreased expression of NPY and BDNF in the brains of these mice.

Effects of estrogen treatment on expression of brain-derived neurotrophic factor and cAMP response element-binding protein expression and phosphorylation in rat amygdaloid and hippocampal structures

Clinical studies indicate an effect of estrogen (E2) on affect and cognition, which may be mediated by the cAMP response element-binding protein (CREB) pathway and CREB-related gene target brain-derived neurotrophic factor (BDNF). We investigated the effect of E2 on CREB expression and phosphorylation and BDNF expression in the amygdala and hippocampus, areas involved in emotional processing. Ovariectomized rats were given 10 microg 17beta-estradiol or vehicle for 14 days and expression of components of the CREB signaling pathway, i.e., CREB, phosphorylated CREB (pCREB), and BDNF in amygdala and hippocampus were investigated using immunogold labeling. Levels of BDNF mRNA were determined by in situ reverse-transcriptase polymerase chain reaction. We also examined the effect of E2 on calcium/calmodulin kinase (CaMK IV) immunolabeling in the hippocampus. E2 increased immunolabeling and mRNA levels of BDNF in the medial and basomedial amygdala and CA1 and CA3 regions of the hippocampus, but not in any other amygdaloid or hippocampal regions examined. E2 increased immunolabeling of CREB and pCREB in the medial and basomedial, but not central or basolateral amygdala. E2 also increased CaMK IV and pCREB immunolabeling in the CA1 and CA3 regions, but not CA2 region or dentate gyrus, of the hippocampus. There was no change in immunolabeling of CREB in any hippocampal region. These data identify a signaling pathway through which E2 increases BDNF expression that may underlie some actions of E2 on affective behavior and indicate neuroanatomical heterogeneity in the E2 effect within the amygdala and hippocampus.

The gene transcription factor cyclic AMP-responsive element binding protein: role in positive and negative affective states of alcohol addiction

The gene transcription factor cyclic adenosine monophosphate (cAMP)-responsive element binding (CREB) protein is a nuclear protein that regulates synaptic plasticity via modulating the expression of several (cAMP)-inducible genes. Alcohol addiction is a complex psychiatric disorder and is characterized by a compulsive and uncontrolled pattern of alcohol drinking by an individual in spite of the adverse consequences of its abuse. Ethanol produces both euphoric (reward and reinforcing) and dysphoric (negative withdrawal reactions) effects and these are most likely involved in the initiation and maintenance of alcohol use and abuse. Several neurotransmitter systems in the brain might be involved in the effects of alcohol but the exact molecular mechanisms of both the positive and negative affective states of alcohol abuse are still unclear. Recent research in molecular neurosciences using animal models have identified the role of extended amygdaloid (shell structures of nucleus accumbens [NAc] and central and medial amygdaloid nuclei) CREB signaling in positive and negative affective states of alcohol drinking behaviors. This review article highlights the current findings on the role of nucleus accumbal and amygdaloid CREB signaling in behavioral consequences of alcohol use and abuse.

Differences in basal levels of CREB and NPY in nucleus accumbens regions between C57BL/6 and DBA/2 mice differing in inborn alcohol drinking behavior

An increasing body of evidence suggests that genetic factors play a role in alcohol drinking behaviors. C57BL/6J (C57) mice innately consume larger amounts of alcohol compared to that consumed by DBA/2J (DBA) mice. Furthermore, alterations in cAMP-responsive element binding (CREB) protein function in the brain have been implicated in alcohol drinking behaviors. The present investigation examined innate expression and phosphorylation of CREB in various brain structures of C57 and DBA mice. It was found that CREB expression and phosphorylation was lower, specifically in the shell structure of the nucleus accumbens, in C57 mice compared to that in DBA mice. CREB expression and phosphorylation were similar in other brain regions such as the nucleus accumbens core and the cortical, amygdaloid, hippocampal, and striatal structures of C57 and DBA mice. The expression of a cAMP-inducible gene, neuropeptide Y (NPY), was also investigated in the nucleus accumbens region of C57 and DBA mice. It was found that in C57 mice, NPY protein levels were lower in the shell but not in the core structure of the nucleus accumbens compared to that in DBA mice. It was also found that C57 mice are not innately anxious, but they consume larger amounts of alcohol than do DBA mice. Because the shell structure of the nucleus accumbens has been implicated in reward mechanisms of alcohol, it is possible that lower CREB function in this brain structure may be in part associated with the excessive alcohol drinking behavior of C57 mice.

Modulation of CREB expression and phosphorylation in the rat nucleus accumbens during nicotine exposure and withdrawal

The nucleus accumbens region of the brain has been shown to play a role in reward and reinforcing mechanisms of drugs of abuse. To understand the molecular mechanisms of nicotine addiction, the present investigation examined the effects of acute and chronic nicotine treatment and its withdrawal on cAMP-responsive element binding (CREB) protein expression and phosphorylation (serine-133) in nucleus accumbens (NAc) structures of rats. it was found that acute treatment (1 and 18 hr of withdrawal) with nicotine had no effects on total creb and phosphorylated CREB (p-CREB) protein levels in shell or core structures of rat NAc. On the other hand, 18-hr withdrawal after chronic nicotine exposure produced significant reductions in the total CREB and p-CREB protein levels in the shell but not in core structures of nac. interestingly, nicotine withdrawal (1 hr) after chronic exposure maintained normal levels of total CREB and p-CREB protein levels in the shell and core structures of NAc. These results suggest the possibility that decreased CREB activity in the shell of NAc may be associated with abnormal reward mechanisms during nicotine withdrawal after chronic exposure.

Serotonin receptors in platelets of bipolar and schizoaffective patients: effect of lithium treatment

RATIONALE

Abnormalities of serotonin (5HT) function have been implicated in mood disorders, and lithium treatment may produce its beneficial effects by modifying serotonergic mechanisms. It has also been observed that 5HT2A receptors are upregulated both in the postmortem brain and platelets of patients with depression and suicidal behavior. However, the role of 5HT2A receptors in bipolar disorders and in the mechanism of action of lithium is unclear.

OBJECTIVE

The major objective of this study was to examine if abnormalities of 5HT2A receptors are associated with bipolar or schizoaffective disorders and if treatment with lithium would cause changes in the 5HT2A receptors.

METHODS

5HT2A receptors were studied in the platelets obtained from drug-free normal control subjects and patients with bipolar ( n=41) or schizoaffective ( n=20) disorders during a drug-free washout period and after treatment (4.0+/-0.44 weeks) with lithium ( n=16). The Bmax and K(D) of 5HT2A receptors were quantitated by binding techniques using [125I]lysergic acid diethylamide (LSD) as a ligand.

RESULTS

We observed that the 5HT2A receptor Bmax was increased in platelets obtained from drug-free bipolar or schizoaffective patients as compared with normal control subjects. The 5HT2A receptor density was even more increased in bipolar or schizoaffective suicidal patients, and the 5HT2A receptor Bmax in the non-suicidal bipolar or schizoaffective subgroup also was significantly higher than in normal control subjects. Treatment with lithium caused a significant increase in the B(max) of platelet 5HT2A receptors in bipolar or schizoaffective patients.

CONCLUSIONS

Our studies indicate that increased 5HT2A receptors may be associated with the pathophysiology of bipolar illness and that treatment with lithium further increases the density of 5HT2A receptors. Whether this increase in 5HT2A receptors caused by lithium is associated with its therapeutic mechanism of action is unclear. It is also not clear whether the increase in 5HT2A receptors in bipolar or schizoaffective patients, or in suicidal bipolar or schizoaffective patients, is a trait or state marker.

Effects of PKA modulation on the expression of neuropeptide Y in rat amygdaloid structures during ethanol withdrawal

We recently reported that neuropeptide Y (NPY) protein levels and cAMP responsive element binding (CREB) protein phosphorylation are lower in amygdaloid structures during ethanol withdrawal after chronic exposure. Furthermore, we reported that normalization of CREB phosphorylation by infusing protein kinase A (PKA) activator into the central amygdala prevents anxiety-like effects in rats during ethanol withdrawal. Here we investigated whether normalization of CREB phosphorylation by infusing PKA activator (Sp-cAMP) into the central amygdala also normalizes the expression of NPY during ethanol withdrawal. Sprague-Dawley male rats were cannulated targeting the central amygdala and then treated either with Lieber-DeCarli ethanol diet or control diet for 15 days. Subsequently ethanol-fed rats were withdrawn for 0 and 24h. The control-diet fed and ethanol-withdrawn rats were infused twice with PKA activator or inhibitor (Rp-cAMP). The protein and mRNA levels of NPY were determined in amygdaloid structures using gold-immunolabeling and the in situ RT-PCR procedure. It was found that chronic ethanol treatment has no effect on mRNA and protein levels of NPY in the central, medial, or basolateral amygdala. On the other hand, ethanol withdrawal produced significant reductions in mRNA and protein levels of NPY in the central and medial but not in the basolateral amygdala. The reductions in mRNA and protein levels of NPY were normalized in the central amygdala by infusion with PKA activator in ethanol-withdrawn rats. On the other hand, PKA-inhibitor infusion does not have any effect on mRNA and protein levels of NPY in the central amygdala of ethanol-withdrawn rats, but significantly decreased the expression of NPY in the central amygdala of control-diet fed rats. These results suggest that the decreased cellular expression of NPY in the central amygdala may play an important role in the CREB-mediated regulation of anxiety-like behaviors during ethanol withdrawal.

Anxiety and alcohol abuse disorders: a common role for CREB and its target, the neuropeptide Y gene

It has been hypothesized that anxiety disorders play an important role in the initiation and maintenance of alcohol drinking behaviors. However, the molecular mechanisms for the association between anxiety and alcohol abuse are not well understood. Structures of the extended amygdala, particularly the central nucleus of amygdala, are involved in anxiety and in motivational aspects of alcohol drinking behaviors. Here, I propose that cAMP response element-binding protein (CREB) has a role in anxiety and alcohol drinking behaviors. The CREB gene transcription factor regulates the expression of the gene encoding neuropeptide Y (NPY), and decreased concentrations of NPY are implicated in anxiety and alcohol drinking behaviors. Therefore, decreased function of CREB in the central nucleus of the amygdala might regulate anxiety and alcohol intake via decreased expression of NPY, and might provide a common link between anxiety and alcohol abuse disorders. I also suggest that, via CREB, NPY might interact with other CREB target genes, such as the gene encoding brain-derived neurotrophic factor, and that this CREB-mediated interaction might be important in the regulation of anxiety and alcohol drinking behaviors.

The decreased phosphorylation of cyclic adenosine monophosphate (cAMP) response element binding (CREB) protein in the central amygdala acts as a molecular substrate for anxiety related to ethanol withdrawal in rats

BACKGROUND

Several lines of evidence indicate a high comorbidity between anxiety and alcohol abuse. This study investigated the molecular mechanisms in the amygdaloid neurocircuitry governing anxiety related to ethanol withdrawal and also the phenomenon of alcohol preference.

METHODS

Male Sprague Dawley(R) rats were treated with ethanol or control diet for 15 days, and ethanol-fed rats were withdrawn for 0 and 24 hr. Ethanol-withdrawn or control diet-fed rats were bilaterally infused into central or basolateral amygdala with artificial cerebrospinal fluid or protein kinase A (PKA) activator or inhibitor. These rats were used to measure anxiety levels by the elevated plus-maze test. Protein levels of various signaling molecules related to cyclic adenosine monophosphate (cAMP)-response element binding (CREB) protein signaling in amygdaloid structures were determined by gold immunolabeling procedure. The messenger RNA levels of neuropeptide Y were determined by in situ polymerase chain reaction procedure.

RESULTS

Ethanol withdrawal (24 hr) after chronic exposure (15 days) produced anxiety in rats as measured by elevated plus-maze test. Ethanol withdrawal but not treatment significantly decreased the phosphorylation of CREB protein and protein levels of Ca2+/calmodulin-dependent protein kinase IV without modulating the protein levels of total CREB and alpha-catalytic subunit of protein kinase A (PKA-Calpha) in the central and medial amygdala. However, these changes were not observed in the basolateral amygdala. We also investigated the effects of manipulation of the phosphorylation status of CREB in the central amygdala by infusion of the PKA activator (Sp-cAMPS) or inhibitor (Rp-cAMPS) on anxiety levels in rats during ethanol withdrawal. When Sp-cAMPS is specifically infused into the central amygdala, it dose-dependently normalizes the decrease in CREB phosphorylation and prevents the development of anxiety in rats during ethanol withdrawal. On the other hand, Rp-cAMPS infusions into the central or basolateral amygdala decrease CREB phosphorylation, but only infusion into the central amygdala provokes anxiety and increases alcohol preference in normal rats. We also found that alcohol preference provoked by decreased CREB phosphorylation is related to decreased expression of the neuropeptide Y gene in the central amygdala.

CONCLUSIONS

These novel results suggest the possibility that decreased CREB phosphorylation in the central amygdala acts as a common molecular correlate for anxiety and alcohol-drinking behaviors and also is correlated with anxiety related to ethanol withdrawal.

Neuropeptide y and alcoholism: genetic, molecular, and pharmacological evidence

This article presents the proceedings of a symposium presented at the combined meeting of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism, held in San Francisco, CA, in June 2002. The organizers and chairpersons were Subhash C. Pandey and Todd E. Thiele. The presentations were (1) Altered ethanol-induced sedation and ethanol drinking in mutant mice lacking specific NPY receptor, by Todd E. Thiele; (2) NPY in P and NP rats: polymorphism and mRNA expression, by Lucinda G. Carr; (3) The cAMP-dependent PKA in the central amygdala regulates alcohol intake through NPY gene, by Subhash C. Pandey; (4) Involvement of NPY in alcohol dependence: from animal models to human genetics, by Markus Heilig; and (5) Association of neuropeptide Y polymorphism with the occurrence of type 1 and type 2 alcoholism, by Erkki Ilveskoski.

The decreased cellular expression of neuropeptide Y protein in rat brain structures during ethanol withdrawal after chronic ethanol exposure

BACKGROUND

Neuropeptide Y (NPY) has been implicated in the alcohol-drinking behaviors of rodents. This study investigated the possible involvement of NPY in the neuroadaptational mechanisms to chronic ethanol exposure and its withdrawal.

METHODS

Male Sprague-Dawley rats were treated either with Lieber-DeCarli ethanol diet or control diet for 15 days, and ethanol-fed rats were withdrawn for 0 and 24 hr. The protein expression of NPY was determined in cortical, hippocampal, amygdaloid, striatal, and hypothalamic structures by using the gold-immunolabeling histochemical procedure.

RESULTS

It was found that ethanol withdrawal, but not ethanol treatment, produced significant reductions in NPY protein levels in (1) layers IV and V of the frontal and parietal cortex, (2) layer II of the piriform cortex, (3) the central and medial nuclei of the amygdala, and (4) the paraventricular nucleus of the hypothalamus in rat brain. Chronic ethanol exposure and its withdrawal had no effect on the NPY protein levels in layers II, III, and VI of the frontal and parietal cortex or cingulate gyrus, in hippocampal (CA1, CA2, CA3, and dentate gyrus) and striatal (caudate putamen and globus pallidus) structures, or in the ventro-medial hypothalamus and basolateral amygdala. However, chronic ethanol exposure and its withdrawal produced significant reductions in NPY protein levels in the arcuate nucleus of the hypothalamus and in layers IV and V of the cingulate gyrus.

CONCLUSIONS

These results suggest that the decreased protein levels of NPY in the central and medial nuclei of the amygdala, as well as in the cortical and hypothalamic structures, during ethanol withdrawal may play an important role in the neuromechanisms of some ethanol withdrawal symptoms.